Mechanical telephone



(No Model.)

W. J. BOWEN. MECHANICAL TELEPHONE.

No. 481,133. Patented Aug. 16,1892.

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WITNESSES mi xonms vnzas cm, PNDTO-LIYHQ, WASHINGYON, u. c.

UNITED STATES PATENT OFFICE.

WILLIAM J. BOWEN, OF NORIVALK, OHIO, ASSIGNOR TO \VILLIAM HUBBARD, OF ELGIN, ILLINOIS.

MECHANICAL TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 481,133, dated August 16, 1892.

Application filed May Z, 1891- Serial No. 391.438. (No model.)

To all whom it may concern.-

Be it known that 1, WILLIAM J. BOWEN, a citizen of the United States, residing at Norwalk, in the county of Huron and State of Ohio, have invented certain new and useful Improvementsin Mechanical Telephones; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which IO it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification, in which- :5 Figure l is a sectional view of my improved mechanical telephone through Fig. 2 at line W W. Fig. 2 is a rear elevation with backboard Z of Fig. I removed. Fig. 3 is a rear view in elevation of bar N, showing a modifi- 2o cation of same. Fig. 4 is a detached sectional View on line as .r, Fig. 2, enlarged.

Similar letters of reference indicate corresponding parts in all of the figures of the draw- Ings.

This invention relates to telephones of the mechanical class, which will be hereinafter more particularly described and pointed out.

A, Fig. 1, is the usual mouthpiece, and B the containing box or case.

O is a round cast-iron plate provided with a flange 0 at the outer edge, into which an iron ringD is fitted. Between said ring D and plate O is placed two insulating-rings F F, one on each side of diaphragm G, the whole being tightly clamped together by means of bolts E, passing through from plate 0 to ring D, holding diaphragm G firmly at its edges, and at the center of the same is placed a button II, to which is connected the line-wire h by means of rod I, all in the same manner as telephones are commonly constructed.

At the back of diaphragm G and clamped at the edges with it is a thin rubber disk L, which is held away from the diaphragm at the center by means of a piece of rubber tube K, forming an air-chamber. Pressing upon disk L at the back is a spiral spring M, which is connected and held by a bar N and formed near the center in the shape of a ring to hold spring M properly, also to allow line-rod I to pass out unobstructed. Bar N is placed diagonally, so that the ends of same may rest in corners of case B, which act as guides to the bar in its forward or backward movement, that is accomplished by means of screws P P, which are threaded into ends of bar N and pass out through front of case B, where the screws are provided with mill-heads R B, so that the bar N can be adjusted to increase or diminish the pressure upon the spring from the outside of the case.

In operation it can be seen that to turn the screw-headsR Rin one direction causes screws P P to draw the barN forward. This in turn causes spring M to increase its pressure upon the disk L, which reduces the air-space and closes the contact toward the center, between disk L and diaphragm G, and which modifies the tone and dampens the false Vibrations or echo and enables the operator to hear conversation over the line much more distinctly than could be done without this device. At the same time the spring M does not interfere with the vibrations of the diaphragm caused by speaking into the mouthpiece A and can be quickly loosened or readjusted, as the conditions may require.

Fig. 3 shows a modification of my device in which the bar N has its ring portion made larger and fiat pressuresprings X X X X substituted for spiral spring M, Fig. 1, said fiat springs X X X X being bent backward toward disk L, producing the same results, by means of screws P P.

Having described my invention, I claim The combination of the screws P P, extend ing outside of the case B, bar N, spiral spring M, disk L, air-tube K, diaphragm G, case B, and mouthpiece A.

In testimony whereof I affix my signaturein 9o presence of two witnesses.

IVILLIAM J. BOWVEN.

Witnesses:

KATHARINE LAWRENCE, E. G. BOUGHTON. 

